Comment by travisoliphant

I think this is true. I have used the Python C-API heavily having started SciPy and NumPy and Numba. I have a pre-alpha plan for addressing the C-API by introducing EPython (a typed subset of Python for extending it). It is not usable and in idea stage only, but I welcome collaborators and funders: https://github.com/epython-dev/epython. Here is a talk that describes a bit more the vision: https://morioh.com/p/6db365736476